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KarlM
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Any thoughts on this paper?
https://arxiv.org/abs/1712.07962
https://arxiv.org/abs/1712.07962
How is 20:0 less imbalanced than 19:1, let alone perfectly balanced?yahastu said:I would point out that if approximately 95% of the mass in the universe is negative rather than positive, then perhaps its actually 100% -- a perfectly equally balanced universe of positive and negative mass, which seems rather elegant.
Bandersnatch said:How is 20:0 less imbalanced than 19:1, let alone perfectly balanced?
Elroch said:negative mass, which has positive energy according to Einstein's energy momentum equation
Elroch said:what is the stress energy tensor for a negative mass density
Great respect for Sabine Hossenfelder. I found her response to a poster named DreamChaser to be of particular interest, DreamChaser said that they liked the study because it was elegant in offering an explanation for both dark energy and dark matter (I will admit that I also found this appealing) and was therefore simpler solution. This was her reply:PeterDonis said:Sabine Hossenfelder has posted about this paper:
http://backreaction.blogspot.com/2018/12/no-negative-masses-have-not.html
Elroch said:A question is whether all positive energies breaks any conservation laws.
yahastu said:If this is dark matter, this explanation tells us why it is "dark" -- specifically, dark matter would be "dark" because these negative mass particles are mutually repulsive
yahastu said:The author explains that this theory corresponds to an Anti-de Sitter space
yahastu said:If this theory is correct I think it also tells us what we could expect to happen if someone tried to fly "to the edge of the universe".
yahastu said:the edge of positive mass
Elroch said:I meant whether energy and momentum are conserved in local Lorentz frames according to the defining interactions
Elroch said:Another concern of mine is whether with such weird dynamics any system with both types of matter could be stable
yahastu said:I found it interesting in section 3.4 where it is pointed out that the runaway motion that is described for positive-negative mass pairs could explain cosmic rays.
Elroch said:Sean Carroll's main point is why I am uncomfortable with negative energy and why I assumed (inconsistently with Franes, it seems) that the energies are all positive and it is only the gravitational interaction that is flipped. I am yet to be completely convinced that this is impossible, but that is not really for this discussion.
PeterDonis said:Unfortunately, the presence of these "runaway motion" solutions predicts a lot more than that: as Hossenfelder points out in her article, it predicts that these pairs of positive-negative mass particles should be constantly being created everywhere and emitting huge amounts of energy all over the place. (An often used term for this is "the vacuum is unstable".) Obviously we do not observe this at all.
PeterDonis said:This has nothing to do with whether or not the negative mass particles can absorb or emit electromagnetic radiation. If they are postulated not to do so, that is an additional assumption that has to be added to the model.
But that requires that negative mass acts like a negative cosmological constant. As I pointed out in post #12, I don't see how that can work.
Elroch said:Whether particles interact with electromagnetic radiation depends simply on whether they have an electric charge. Any other interaction of photons would be a surprising additional assumption.
yahastu said:it was observed that galaxy rotation curves do not agree with the predictions of GR.
yahastu said:it was argued that the theory is infallible
yahastu said:Dark matter is not something that was predicted in advance by any theory.
yahastu said:Farnes only proposed a creation term of negative mass particles, not positive ones...so I don't think you'd have positive-negative mass pairs spontaneously appearing in the vacuum.
yahastu said:when a positive mass encounters a negative mass, it wouldn't lead to the creation of new energy